Sunday, April 6

2008 Grasshopper Forecast Shows Few Pockets of Concern

Source: Saskatchewan Agriculture and Food

It appears that most of Saskatchewan should be relatively safe from major grasshopper infestations for 2008, although there are some pockets of concern around the province.

That's the prognosis contained in the "2008 Grasshopper Forecast" compiled by the Saskatchewan Ministry of Agriculture in conjunction with Saskatchewan Crop Insurance.

The forecast, along with a corresponding colour-coded map showing the projected infestation risk across the province, has now been posted on the ministry's website at http://www.agriculture.gov.sk.ca/.

"Overall, it looks like the majority of the province falls into the ‘none to very light' category, where the grasshopper population should not be a problem," said Dale Risula, the Integrated Crop Management Systems Specialist with the Agriculture Knowledge Centre in Moose Jaw.

"There are a few isolated regions that have the potential for large populations of grasshoppers in 2008, but those are very small, particular areas," he added. "It appears that there may be three or four specific zones that could encounter some difficulties."

The forecast is based on the adult grasshopper counts observed during August and early September 2007 by Saskatchewan Crop Insurance field staff. The survey includes more than 1,100 sites throughout the province. The forecast is based on adult grasshoppers capable of reproduction. This provides an estimate of the number of eggs that may hatch the following spring and present a risk to crops in 2008.

"The forecast is not an absolute certainty," Risula noted. "It is just to say what the probability or the foundation is for grasshopper numbers in the upcoming growing season."

The primary factor determining actual grasshopper numbers will be the weather next spring.

"The hatch in the springtime is going to depend on growing degree days, which is a measure of accumulated heat units. If it's a dry, warm spring and the soil heats up fairly significantly, you could see an increase in the hatch numbers that take place. If it's a cold, wet spring, you will probably see populations kept at bay."

Populations can be affected by several other factors, including the presence of predatory insects, as well as the incidence of disease.

According to Risula, just about every crop grown in Saskatchewan is at some degree of risk from grasshopper damage. With cereals, grasshoppers generally consume the leaf material, which reduces the photosynthetic ability of the plant. With crops like lentil or flax, they usually attack the pods or bolls, which directly impacts yield.

In other crops such as canola, mustard or pea, grasshoppers may present an additional problem. "If they are present when the crop is being combined, their body parts can get picked up in the harvest and contaminate the sample, lowering the seed quality and requiring further processing," Risula said.

"Even in those areas where projections are low, producers would be well-served keeping a close eye on the situation, since infestations can vary widely on a field-by-field basis."

More information and advice on grasshopper projections and control methods can be found on the Saskatchewan Agriculture website or by calling the Agriculture Knowledge Centre at 1-866-457-2377.

For more information, contact:
Dale Risula, Integrated Cropping Management Systems Specialist
Saskatchewan Ministry of Agriculture
Phone: (306) 694-3714
E-mail: drisula@agr.gov.sk.ca
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